Collingwood fear Adam Treloar's AFL season could be over because of his bizarre hamstring injuries.
At best, one of the in-form Magpies' most important players will be out of action for more than a month, in a major blow to their season.
Club president Eddie McGuire says the worst-case scenario is that the star midfielder needs significant surgery and is out of action for more than 10 weeks.
Treloar hurt his two hamstrings when he was pushed from behind while sprinting along the MCG wing during Sunday's win over Carlton.
McGuire said it extremely rare for someone to hurt the two hamstrings in the same incident.
Treloar initially thought it was hamstring cramp and coach Nathan Buckley also was optimistic in his post-game media conference.
But scans on Monday morning have shown damage to the two hamstrings.
The Magpies are worried more about the left hamstring tendon and Treloar will consult a surgeon on Tuesday.
"Everyone was up on their toes ... we left the MCG thinking we might have dodged a bullet there," McGuire said on AFL360.
"If he needs to have surgery, well probably eight to 10 weeks is optimistic and then we know what the pessimistic answer to that is.
"We want to get the surgeon to get in and have a look."
McGuire then was asked if it could be season over for the Brownlow Medal fancy.
"You're always fearful, but I'm also hopeful that he hasn't - I'm hopeful it's a six to eight or maybe an eight to 10 at worst," he added.
"That would be the best result.
"Obviously if he needs to have major surgery, then it's season over."
While Collingwood are cursing their luck - it continues their bad run with injuries - McGuire said they would fight back.
The Magpies have risen to fourth on the back of a five-game winning streak as they try to make the finals for the first time since 2013.
"It's unheard of - we come up with a new one every week, don't we," McGuire said of Treloar's double hamstring blow.
"(But) there is a feeling at our club of optimism at the moment and genuine lightness in our step, where it might have been heavy in the past.
"A day like today would have been a dagger through the heart ... you know what? We're going to reload and we're going to go again."
Earlier on Monday, Treloar was unsure about his fate after undergoing the hamstring scans.
"It just felt like a cramp, that's why we're trying to suss out what's going on," he said.
"I've never done a soft tissue (injury) or anything so I don't really know what's happened.
"(I feel) a bit sore obviously, it feels okay.
"I can't really compare it to anything else because I've never (done a hamstring) - I will find out in the next 24 hours I guess."